[NETFILTER]: nf_nat: pass manip type instead of hook to nf_nat_setup_info
[linux-2.6.git] / net / ipv4 / netfilter / nf_conntrack_proto_icmp.c
1 /* (C) 1999-2001 Paul `Rusty' Russell
2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8
9 #include <linux/types.h>
10 #include <linux/timer.h>
11 #include <linux/netfilter.h>
12 #include <linux/in.h>
13 #include <linux/icmp.h>
14 #include <linux/seq_file.h>
15 #include <net/ip.h>
16 #include <net/checksum.h>
17 #include <linux/netfilter_ipv4.h>
18 #include <net/netfilter/nf_conntrack_tuple.h>
19 #include <net/netfilter/nf_conntrack_l4proto.h>
20 #include <net/netfilter/nf_conntrack_core.h>
21
22 static unsigned long nf_ct_icmp_timeout __read_mostly = 30*HZ;
23
24 static int icmp_pkt_to_tuple(const struct sk_buff *skb,
25                              unsigned int dataoff,
26                              struct nf_conntrack_tuple *tuple)
27 {
28         struct icmphdr _hdr, *hp;
29
30         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
31         if (hp == NULL)
32                 return 0;
33
34         tuple->dst.u.icmp.type = hp->type;
35         tuple->src.u.icmp.id = hp->un.echo.id;
36         tuple->dst.u.icmp.code = hp->code;
37
38         return 1;
39 }
40
41 /* Add 1; spaces filled with 0. */
42 static const u_int8_t invmap[] = {
43         [ICMP_ECHO] = ICMP_ECHOREPLY + 1,
44         [ICMP_ECHOREPLY] = ICMP_ECHO + 1,
45         [ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
46         [ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
47         [ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
48         [ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
49         [ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
50         [ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1
51 };
52
53 static int icmp_invert_tuple(struct nf_conntrack_tuple *tuple,
54                              const struct nf_conntrack_tuple *orig)
55 {
56         if (orig->dst.u.icmp.type >= sizeof(invmap)
57             || !invmap[orig->dst.u.icmp.type])
58                 return 0;
59
60         tuple->src.u.icmp.id = orig->src.u.icmp.id;
61         tuple->dst.u.icmp.type = invmap[orig->dst.u.icmp.type] - 1;
62         tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
63         return 1;
64 }
65
66 /* Print out the per-protocol part of the tuple. */
67 static int icmp_print_tuple(struct seq_file *s,
68                             const struct nf_conntrack_tuple *tuple)
69 {
70         return seq_printf(s, "type=%u code=%u id=%u ",
71                           tuple->dst.u.icmp.type,
72                           tuple->dst.u.icmp.code,
73                           ntohs(tuple->src.u.icmp.id));
74 }
75
76 /* Print out the private part of the conntrack. */
77 static int icmp_print_conntrack(struct seq_file *s,
78                                 const struct nf_conn *conntrack)
79 {
80         return 0;
81 }
82
83 /* Returns verdict for packet, or -1 for invalid. */
84 static int icmp_packet(struct nf_conn *ct,
85                        const struct sk_buff *skb,
86                        unsigned int dataoff,
87                        enum ip_conntrack_info ctinfo,
88                        int pf,
89                        unsigned int hooknum)
90 {
91         /* Try to delete connection immediately after all replies:
92            won't actually vanish as we still have skb, and del_timer
93            means this will only run once even if count hits zero twice
94            (theoretically possible with SMP) */
95         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
96                 if (atomic_dec_and_test(&ct->proto.icmp.count)
97                     && del_timer(&ct->timeout))
98                         ct->timeout.function((unsigned long)ct);
99         } else {
100                 atomic_inc(&ct->proto.icmp.count);
101                 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
102                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmp_timeout);
103         }
104
105         return NF_ACCEPT;
106 }
107
108 /* Called when a new connection for this protocol found. */
109 static int icmp_new(struct nf_conn *conntrack,
110                     const struct sk_buff *skb, unsigned int dataoff)
111 {
112         static const u_int8_t valid_new[] = {
113                 [ICMP_ECHO] = 1,
114                 [ICMP_TIMESTAMP] = 1,
115                 [ICMP_INFO_REQUEST] = 1,
116                 [ICMP_ADDRESS] = 1
117         };
118
119         if (conntrack->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new)
120             || !valid_new[conntrack->tuplehash[0].tuple.dst.u.icmp.type]) {
121                 /* Can't create a new ICMP `conn' with this. */
122                 pr_debug("icmp: can't create new conn with type %u\n",
123                          conntrack->tuplehash[0].tuple.dst.u.icmp.type);
124                 NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
125                 return 0;
126         }
127         atomic_set(&conntrack->proto.icmp.count, 0);
128         return 1;
129 }
130
131 /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
132 static int
133 icmp_error_message(struct sk_buff *skb,
134                  enum ip_conntrack_info *ctinfo,
135                  unsigned int hooknum)
136 {
137         struct nf_conntrack_tuple innertuple, origtuple;
138         struct nf_conntrack_l4proto *innerproto;
139         struct nf_conntrack_tuple_hash *h;
140
141         NF_CT_ASSERT(skb->nfct == NULL);
142
143         /* Are they talking about one of our connections? */
144         if (!nf_ct_get_tuplepr(skb,
145                                skb_network_offset(skb) + ip_hdrlen(skb)
146                                                        + sizeof(struct icmphdr),
147                                PF_INET, &origtuple)) {
148                 pr_debug("icmp_error_message: failed to get tuple\n");
149                 return -NF_ACCEPT;
150         }
151
152         /* rcu_read_lock()ed by nf_hook_slow */
153         innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum);
154
155         /* Ordinarily, we'd expect the inverted tupleproto, but it's
156            been preserved inside the ICMP. */
157         if (!nf_ct_invert_tuple(&innertuple, &origtuple,
158                                 &nf_conntrack_l3proto_ipv4, innerproto)) {
159                 pr_debug("icmp_error_message: no match\n");
160                 return -NF_ACCEPT;
161         }
162
163         *ctinfo = IP_CT_RELATED;
164
165         h = nf_conntrack_find_get(&innertuple);
166         if (!h) {
167                 pr_debug("icmp_error_message: no match\n");
168                 return -NF_ACCEPT;
169         }
170
171         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
172                 *ctinfo += IP_CT_IS_REPLY;
173
174         /* Update skb to refer to this connection */
175         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
176         skb->nfctinfo = *ctinfo;
177         return -NF_ACCEPT;
178 }
179
180 /* Small and modified version of icmp_rcv */
181 static int
182 icmp_error(struct sk_buff *skb, unsigned int dataoff,
183            enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
184 {
185         struct icmphdr _ih, *icmph;
186
187         /* Not enough header? */
188         icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih);
189         if (icmph == NULL) {
190                 if (LOG_INVALID(IPPROTO_ICMP))
191                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
192                                       "nf_ct_icmp: short packet ");
193                 return -NF_ACCEPT;
194         }
195
196         /* See ip_conntrack_proto_tcp.c */
197         if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
198             nf_ip_checksum(skb, hooknum, dataoff, 0)) {
199                 if (LOG_INVALID(IPPROTO_ICMP))
200                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
201                                       "nf_ct_icmp: bad HW ICMP checksum ");
202                 return -NF_ACCEPT;
203         }
204
205         /*
206          *      18 is the highest 'known' ICMP type. Anything else is a mystery
207          *
208          *      RFC 1122: 3.2.2  Unknown ICMP messages types MUST be silently
209          *                discarded.
210          */
211         if (icmph->type > NR_ICMP_TYPES) {
212                 if (LOG_INVALID(IPPROTO_ICMP))
213                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
214                                       "nf_ct_icmp: invalid ICMP type ");
215                 return -NF_ACCEPT;
216         }
217
218         /* Need to track icmp error message? */
219         if (icmph->type != ICMP_DEST_UNREACH
220             && icmph->type != ICMP_SOURCE_QUENCH
221             && icmph->type != ICMP_TIME_EXCEEDED
222             && icmph->type != ICMP_PARAMETERPROB
223             && icmph->type != ICMP_REDIRECT)
224                 return NF_ACCEPT;
225
226         return icmp_error_message(skb, ctinfo, hooknum);
227 }
228
229 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
230
231 #include <linux/netfilter/nfnetlink.h>
232 #include <linux/netfilter/nfnetlink_conntrack.h>
233
234 static int icmp_tuple_to_nlattr(struct sk_buff *skb,
235                                 const struct nf_conntrack_tuple *t)
236 {
237         NLA_PUT_BE16(skb, CTA_PROTO_ICMP_ID, t->src.u.icmp.id);
238         NLA_PUT_U8(skb, CTA_PROTO_ICMP_TYPE, t->dst.u.icmp.type);
239         NLA_PUT_U8(skb, CTA_PROTO_ICMP_CODE, t->dst.u.icmp.code);
240
241         return 0;
242
243 nla_put_failure:
244         return -1;
245 }
246
247 static const struct nla_policy icmp_nla_policy[CTA_PROTO_MAX+1] = {
248         [CTA_PROTO_ICMP_TYPE]   = { .type = NLA_U8 },
249         [CTA_PROTO_ICMP_CODE]   = { .type = NLA_U8 },
250         [CTA_PROTO_ICMP_ID]     = { .type = NLA_U16 },
251 };
252
253 static int icmp_nlattr_to_tuple(struct nlattr *tb[],
254                                 struct nf_conntrack_tuple *tuple)
255 {
256         if (!tb[CTA_PROTO_ICMP_TYPE]
257             || !tb[CTA_PROTO_ICMP_CODE]
258             || !tb[CTA_PROTO_ICMP_ID])
259                 return -EINVAL;
260
261         tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMP_TYPE]);
262         tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMP_CODE]);
263         tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMP_ID]);
264
265         if (tuple->dst.u.icmp.type >= sizeof(invmap)
266             || !invmap[tuple->dst.u.icmp.type])
267                 return -EINVAL;
268
269         return 0;
270 }
271 #endif
272
273 #ifdef CONFIG_SYSCTL
274 static struct ctl_table_header *icmp_sysctl_header;
275 static struct ctl_table icmp_sysctl_table[] = {
276         {
277                 .procname       = "nf_conntrack_icmp_timeout",
278                 .data           = &nf_ct_icmp_timeout,
279                 .maxlen         = sizeof(unsigned int),
280                 .mode           = 0644,
281                 .proc_handler   = &proc_dointvec_jiffies,
282         },
283         {
284                 .ctl_name = 0
285         }
286 };
287 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
288 static struct ctl_table icmp_compat_sysctl_table[] = {
289         {
290                 .procname       = "ip_conntrack_icmp_timeout",
291                 .data           = &nf_ct_icmp_timeout,
292                 .maxlen         = sizeof(unsigned int),
293                 .mode           = 0644,
294                 .proc_handler   = &proc_dointvec_jiffies,
295         },
296         {
297                 .ctl_name = 0
298         }
299 };
300 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
301 #endif /* CONFIG_SYSCTL */
302
303 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly =
304 {
305         .l3proto                = PF_INET,
306         .l4proto                = IPPROTO_ICMP,
307         .name                   = "icmp",
308         .pkt_to_tuple           = icmp_pkt_to_tuple,
309         .invert_tuple           = icmp_invert_tuple,
310         .print_tuple            = icmp_print_tuple,
311         .print_conntrack        = icmp_print_conntrack,
312         .packet                 = icmp_packet,
313         .new                    = icmp_new,
314         .error                  = icmp_error,
315         .destroy                = NULL,
316         .me                     = NULL,
317 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
318         .tuple_to_nlattr        = icmp_tuple_to_nlattr,
319         .nlattr_to_tuple        = icmp_nlattr_to_tuple,
320         .nla_policy             = icmp_nla_policy,
321 #endif
322 #ifdef CONFIG_SYSCTL
323         .ctl_table_header       = &icmp_sysctl_header,
324         .ctl_table              = icmp_sysctl_table,
325 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
326         .ctl_compat_table       = icmp_compat_sysctl_table,
327 #endif
328 #endif
329 };